Grammar fixes/standardize on yarn.

Author: Ryan P.C. McQuen

README.md

@@ -42,16 +42,16 @@ Features:
 
 [![https://chrome.google.com/webstore/detail/json-viewer/gbmdgpbipfallnflgajpaliibnhdgobh](https://raw.githubusercontent.com/tulios/json-viewer/master/tryitnow.png)](https://chrome.google.com/webstore/detail/json-viewer/gbmdgpbipfallnflgajpaliibnhdgobh)
 
-### or compile and load by yourself
+### Or compile and load by yourself
 
-  1. it depends on node (version in `package.json` engines)
+  1. It depends on node (version in `package.json` engines).
   2. `npm install --global yarn`
   2. `yarn install`
-  3. `npm run build`
-  4. open Chrome and go to chrome://chrome/extensions/
-  5. enable "Developer mode"
-  6. click "Load unpacked extension"
-  7. select "build/json_viewer" directory
+  3. `yarn run build`
+  4. Open Chrome and go to: chrome://extensions/
+  5. Enable: "Developer mode"
+  6. Click: "Load unpacked extension"
+  7. Select: "build/json_viewer" directory.
 
 ## Try it on